CREDIT QUALITY ASSESSMENT (Restructured Loans at the date of Restructuring For Specific Segments of the Loan Portfolio) (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	$ 2,783	$ 2,359
Specific allowance	935	401
Restructured and subsequently defaulted	0	0
All Other Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	0	364
Specific allowance	0	0
Restructured and subsequently defaulted	0	0
Troubled debt restructurings:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured accruing	322	1,309
Restructured non-accruing	2,461	1,050
Troubled debt restructurings: \| All Other Loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured accruing	0	364
Restructured non-accruing	0	0
Commercial real estate: \| Commercial investor real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	723	1,564
Specific allowance	49	205
Restructured and subsequently defaulted	0	0
Commercial real estate: \| Commercial owner-occupied real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	930	0
Specific allowance	19	0
Restructured and subsequently defaulted	0	0
Commercial real estate: \| Commercial AD&C
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	0	0
Specific allowance	0	0
Restructured and subsequently defaulted	0	0
Commercial real estate: \| Troubled debt restructurings: \| Commercial investor real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured accruing	0	775
Restructured non-accruing	723	789
Commercial real estate: \| Troubled debt restructurings: \| Commercial owner-occupied real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured accruing	0	0
Restructured non-accruing	930	0
Commercial real estate: \| Troubled debt restructurings: \| Commercial AD&C
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured accruing	0	0
Restructured non-accruing	0	0
Commercial Business
Financing Receivable, Troubled Debt Restructuring [Line Items]
Balance	1,130	431
Specific allowance	867	196
Restructured and subsequently defaulted	0	0
Commercial Business \| Troubled debt restructurings:
Financing Receivable, Troubled Debt Restructuring [Line Items]
Restructured accruing	322	170
Restructured non-accruing	$ 808	$ 261

- Definition

Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

+ References

No definition available.

+ Details

Name:	sasr_FinancingReceivableModificationSubsequentDefaultRecordedInvestment
Namespace Prefix:	sasr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months.

+ References

No definition available.

+ Details

Name:	sasr_FinancingReceivableTroubledDebtRestructuringsBalancePrevious12Months
Namespace Prefix:	sasr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which restructured accruing.

+ References

No definition available.

+ Details

Name:	sasr_FinancingReceivableTroubledDebtRestructuringsRestructuredAccruingPrevious12Months
Namespace Prefix:	sasr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which restructured non accruing.

+ References

No definition available.

+ Details

Name:	sasr_FinancingReceivableTroubledDebtRestructuringsRestructuredNonAccruingPrevious12Months
Namespace Prefix:	sasr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of investment related to financing receivables modified by troubled debt restructurings previous 12 months, for specific allowance.

+ References

No definition available.

+ Details

Name:	sasr_FinancingReceivableTroubledDebtRestructuringsSpecificAllowance
Namespace Prefix:	sasr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_FinancingReceivableModificationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=sasr_AllOtherMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=sasr_TroubledDebtRestructuringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_InvestorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=sasr_OwnerOccupiedRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=sasr_AcquisitionDevelopmentAndConstructionMortgageLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: